title: Biomimetic mineralisation of phosphorylated dentine by CPP-ACP.
abstract: OBJECTIVE
  Casein phosphopeptide-amorphous calcium phosphate (CPP-ACP) has the potential to induce the biomimetic mineralisation of dentine collagen fibrils. This study aimed to demonstrate in vitro the ability of CPP-ACP to form apatite crystals on phosphorylated dentine collagen fibrils.
  
  
  METHODS
  Dentine slices with a 2-mm thickness were prepared from sound human third molars. The slices were etched with phosphoric acid to expose the collagen fibres. Sodium trimetaphosphate was then used to phosphorylate the exposed collagen fibres. CPP-ACP paste was topically applied to the surface of the phosphorylated slices, which were then immersed in a metastable calcium phosphate remineralising solution and incubated at 37°C for 10 days. The CPP-ACP paste and the remineralising solution were replaced every two days. Phosphorylated dentine slices without a CPP-ACP application and non-phosphorylated dentine slices with a CPP-ACP application were prepared and used for comparison. The slices were examined using scanning electron microscope (SEM), diffuse reflectance-Fourier transform infrared spectroscopy (DR-FTIR) and X-ray diffraction (XRD).
  
  
  RESULTS
  The SEM results revealed the presence of intrafibrillar and interfibrillar crystal nucleation and growth along the phosphorylated dentine collagen fibres. The DR-FTIR and XRD confirmed that the crystals were hydroxyapatite. No apatite crystal nucleation and growth were observed in either the slices that had no non-phosphorylation or those without CPP-ACP application.
  
  
  CONCLUSIONS
  CPP-ACP can induce the biomimetic mineralisation of dentine through apatite formation along and between the phosphorylated dentine collagen fibres.
  
  
  CONCLUSIONS
  The in vitro study imitated the application of CPP-ACP to exposed dentine tooth surfaces in the mouth. This could lead to the development of a new therapeutic technique for the treatment of tooth hypersensitivity.
authors.affiliation: Faculty of Dentistry, The University of Hong Kong, China.
authors.forename: Ying
authors.initials: Y
authors.lastname: Cao
authors.forename: May L
authors.initials: ML
authors.lastname: Mei
authors.forename: Jianguang
authors.initials: J
authors.lastname: Xu
authors.forename: Edward C M
authors.initials: EC
authors.lastname: Lo
authors.forename: Quanli
authors.initials: Q
authors.lastname: Li
authors.forename: Chun Hung
authors.initials: CH
authors.lastname: Chu
mesh_terms: D000134:Acid Etching, Dental / Q000379:methods; D001031:Apatites / Q000737:chemistry; D040761:Biomimetic Materials / Q000494:pharmacology*; D002113:Calcification, Physiologic / Q000187:drug effects*; D002130:Calcium Phosphates / Q000494:pharmacology; D002364:Caseins / Q000494:pharmacology*; D011232:Chemical Precipitation; D003094:Collagen / Q000737:chemistry / Q000187:drug effects*; D003460:Crystallization; D003804:Dentin / Q000737:chemistry / Q000187:drug effects*; D017886:Durapatite / Q000737:chemistry; D006801:Humans; D008855:Microscopy, Electron, Scanning; D053758:Nanoparticles / Q000737:chemistry; D010756:Phosphoric Acids / Q000737:chemistry; D010766:Phosphorylation; D056951:Photoelectron Spectroscopy; D011122:Polyphosphates / Q000737:chemistry; D017550:Spectroscopy, Fourier Transform Infrared; D013696:Temperature; D013997:Time Factors; D014089:Tooth Remineralization; D014961:X-Ray Diffraction
chemical_list: D001031:Apatites; D002130:Calcium Phosphates; D002364:Caseins; D010756:Phosphoric Acids; D011122:Polyphosphates; C447032:casein phosphopeptide-amorphous calcium phosphate nanocomplex; D003094:Collagen; D017886:Durapatite; C020243:calcium phosphate; C030242:phosphoric acid; C009293:trimetaphosphoric acid
keywords: Biomimetic mineralisation; CPP-ACP; Dentine collagen; Hydroxyapatite; Intrafibrillar; STMP